Printer with detent means on the print motion producing means



Oct. 15, 1968 R. P. MEANS 3,405,794

PRINTER WITH DETENT MEANS THE PRINT MOTION PRODUCING NS Filed Oct. 22, 1965 5 Sheets-Sheet 1 5 .9 llllllz" r RALPH P. MEANS ATTORNEYS R. P. MEANS PRINTER WITH DETENT MEANS ON THE PRINT MOTION PRODUCING MEANS Oct. 15, 1968 5 Sheets-Sheet 2 Filed Oct. 22. 1965 INVENTOR RALPH P. MEANS ATTORNEY;

Oct. 1:), 1968 R. P. MEANS 3,405,794

PRINTER WITH DETENT MEANS ON THE PRINT MOTION PRODUCING MEANS Filed on. 22, 1965 5 Sheets-Sheet s INVENTOR RALPH P. MEANS BY K m ATTORNEYS Oct. 15, 1968 R. P. MEANS 3,405,794

PRINTER WITH DETENT MEANS ON THE PRINT MOTION PRODUCING MEANS "lled Oct 22 1965 5 Sheets-Sheet 4 RALPH P. MEANS Oct. 15, 1968 R MEANS 3,405,794

PRINTER WITH DETENT MEANS ON THE PRINT MOTION PRODUCING MEANS Filed Oct. 22, 1965 5 Sheets-Sheet 5 INVENTOR RALPH P. MEANS ATTORNEYS United States Patent 3,405,794 PRINTER WITH DETENT MEANS ON THE PRHIT MOTION PRDDUCING MEANS Ralph P. Means, Melbourne, Fla., assignor to Soroban Engineering, Inc., Melbourne, Fla., a corporation of Florida Filed Oct. 22, 1965, Ser. No. 591,060 22 Claims. (Cl. 197-55) The present invention relates to high speed serial typewriters capable of printing at rates from 60 to 120 characters per second and, more particularly, to a carriage mechanism and certain peripheral elements for high speed typewriters.

It is an object of the present invention to provide a carriage mechanism for high speed typewriters which carriage mechanism incorporates therein all of the elements necessary to respond to selective rotation of three shafts to accurately position a selected character adjacent a platen and to effect printing of the selected character.

It is another object of the present invention to provide a carriage mechanism for high speed typewriters which mechanism includes a generally cylindrical type font rotatable about and translatable along its axis to select an indicia to be printed and incorporating a printing mechanism which effects final positioning of the selected character and detents the type font during the printing operation.

It is still another object of the present invention to provide a carriage mechanism for a high speed typewriter which mechanism employs detenting means for effecting final positioning of a selected indicia relative to a platen so that the mechanisms for selecting the indicia to be printed or typed may contain a substantial amount of back-lash, thus materially reducing the cost of manufacture of same.

It is another object of the present invention to provide a novel shift mechanism for the high speed typewriter of the present invention.

Yet another object of the present invention is to provide a print actuating apparatus for high speed typewriters which effects both positive print and return movements of the indicia-bearing member.

Still another object of the present invention is to provide a carriage mechanism for high speed typewriters which mechanism is unusually light in weight, simple in construction and economical to manufacture.

It is still another object of the present invention to provide a carriage mechanism for high speed typewriters which mechanism responds only to rotary input motions, thus reducing the forces required to effect selection of a character to be printed even though the carriage mechanism is required to laterally traverse the width of the entire page on which printing is to occur.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of one specific embodiment thereof, especially when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a perspective view of the carriage mechanism of the present invention and the various external operating mechanisms for applying rotary motions to the carriage to effect character selection and printing;

FIGURE 2 is a side view in elevation of the carriage mechanism of the present invention;

FIGURE 3 is a front view in elevation of the carriage mechanism of the present invention;

FIGURE 4 is a cross-sectional view in elevation taken along line 44 of FIGURE 2;

FIGURE 5 is a top view of the carriage mechanism taken along line 55 of FIGURE 2;

FIGURE 6 is a partial cross-sectional side view in elevation taken along lines 6-6 of FIGURE 3;

FIGURE 7 is a perspective view of the print operating apparatus of the carriage mechanism;

FIGURE 8 is a detailed view of an end of one of the print actuating arms of the apparatus of FIGURE 7; and

FIGURE 9 is a schematic diagram in perspective of a portion of a digital positioner which may be employed with the apparatus of the invention and of a portion of the shift mechanism employed herein.

Referring specifically to FIGURE 1 of the accompanying drawings, there is provided a typewriter carriage 1 adapted to transport a type font 2 across a page to be printed. The type font 2 comprises a cylindrical member having a generally vertical axis and including eight horizontal rows 4 of characters or other indicia formed thereon. The font 2 may comprise any given number of rows and columns of indicia but generally 8 or 16 rows or columns of indicia are provided, depending upon the type of apparatus desired. For example, if eight columns and eight rows of indica are employed, sixty-four characters may be printed, whereas if sixteen vertical columns of indicia are employed, one hundred twenty-eight characters may be printed. When the type font contains eight rows and columns, it is common practice to use a pair of simple three binary digit digital positioners to position the font. As will become apparent subsequently, an auxiliary push solenoid 7 is employed if sixteen columns of indicia are provided in either rows or columns on the type font 2.

The type font 2 is hollow along its longitudinal axis and is splined to mate with a splined shaft 8 so that rotation of the shaft 8 produces rotation of the font 2. As will be described in greater detail in the embodiment shown,

H the shaft 8 may assume one of eight different positions if an eight-faced font 2 is employed or may assume sixteen different positions if a sixteen-faced font is employed. Thus, any one of the vertical columns of indicia may be presented to a platen 5 (see FIGURE 2), against which printing is to be effected; the selected column assuming the position of the column 6', indicated in FIGURE 1. An ink ribbon 10 is passed between the font and platen and is incrementally fed in a completely conventional manner.

Vertical movement of the type font 2 is effected by a type font frame 9 which is moved vertically to select a horizontal row 4 for printing. The member 9 is a foursided hollow member having top and bottom walls 11 and 12 and sidewalls 13 and 14. The frame is constrained by the font shaft 8 and the hammer yoke composed of 4-6, 47, 48. The shaft 8 passes vertically through the top and bottom walls 11 and 12, respectively, and is freely rotatable therein. The spacing between the top and bottom walls 11 and 12 is substantially equal to the vertical height of the cylindrical type font 2 and thus, when the member 9 is moved vertically, the font 2 moves therewith sliding along the splinesin the shaft 8.

The shaft 8, and reference is made specifically to FIG- URE 7 ofthe accompanying drawings, is rotatably supported in a yoke 16 having two stub shafts 17 and 18 extending outwardly from the upper ends of the arms of the yoke. The stub shafts 17 and 18 are pivotably secured in bosses 19 and 21 (see FIGURE 3) formed in the typewriter carriage 1 so that the entire assembly is rotatable about the axis of the bores in the bosses 19 and 21 with the top of shaft 8 free to translate in a plane perpendicular to the axis of the bores 19 and 21.

The shaft 8 carries a helical gear 22, adjacent the bottom thereof, adapted to mate with a helical gear 23 carried on a sleeve 24, secured in the carriage 1. The sleeve 24 is freely rotatable about its longitudinal axis in the carriage 1, being supported by roller bearings, not

illustrated, but adapted to be forced into hubs 26 and 27 formed along opposite side surfaces of the carriage 1. The sleeve 24 is internally splined so as to mate with splines formed on a shaft 28 which extends between and is rotatably supported in the fixed frame members 29 and 31. Upon rotation of shaft 28, the helical gear 23 is rotated producing rotation of the helical gear 22 and thus producing rotation of the shaft 8.

The shaft 28 is adapted to assume one of eight, when eight vertical columns of type formed on the font 2, different positions and positioning is effected by a digital positioner such as illustrated and claimed in US. Patent No. 3,089,413 to MacNeill et al., issued on May 13, 1963. Referring specifically to FIGURE 9 of the accompanying drawings, a small portion of the digital positioncr is reproduced therein. The reference numerals applied to digital positioner members in FIGURE 9 are the same as the numerals employed in FIGURE 1 of the aforesaid patent. The positioner can provide one of eight distinct positions of a spline shaft 102 in accordance with information applied to the positioner. The shaft carries a gear 101 which mates with teeth on a rack gear 99. As the rack gear 99 is translated Vertically, the shaft 101 is rotated. The rack gear 99 is translated by means of a pinion 98 on a yoke end of an arm 86 positioned by an eccentric 85. The pinion 98 drives rack 99 in accordance with the position of the arm 86 and a rack 97 which is positioned from a previous stage of the digital positioner. The eccentric is secured to a shaft 83 carrying a gear 79. The gear 79 is rotated by the apparatus of the digital positioner to insert the most significant digit into a mechanical digital summation apparatus, the sum of the various inputs of which appear in the form of translation of the rack gear 99. Specifically, upon intermittent rotation of the gear 79, the eccentric 85 of the aforesaid patent is selectively rotated, selectively moving the arm 86 up or down so as to produce rotation of the gear 98 which cooperates with teeth on the rack gear 99 to vertically translate the output rack gear of the digital positioner.

Since three bits of information may be inserted into the digital positioner illustrated in the aforesaid patent, any one of eight distinct positions may be selected. These positions appear as different degrees of rotation of the shaft 102 rotatably supported in a frame member 31 of the apparatus of the present invention, reference being made to FIGURE 1 hereof. The production versions of the digital positioner described in the aforesaid patent only provide for positioning the output rack 99 to a precision of three binary digits or one in eight discrete positions. To permit positioning to another binary digit or one in sixteen without complete redesign, a set of helical gears is inserted in shaft 102 as will be described.

The splined shaft 102 has secured to the right end thereof as viewed in FIGURES l and 9 an external helical gear 33, movement thereof parallel to the axis of shaft 102 being prevented by a set screw. The gear 33 is situated within a housing member 35 having disposed therein an internal helical gear 36 which mates with gear 33. The housing 35 is secured to the left end of shaft 28 as viewed in FIGURES 1 and 9 and longitudinal translation of 35 is prevented by a set screw 40.

If up to eight faces are provided on the font 2, a direct connection may be made between the shaft 102 and the shaft 28, and in fact, the shaft 28 may constitute an extension of the shaft 102. However, when up to sixteen vertical columns are provided on the font 2, the arrangement illustrated in FIGURE 9 is required. The gearing, specifically between the gear 101 and the rack gear 99, is such that but eight vertical columns on the font 2 may be selected. However, the shaft 28, when a sixteen-vertical-column font is employed, is axially translatable by means of the solenoid 7. A compression spring arrangement 37 normally maintains the shaft 28, as viewed in FIGURE 1, in its furthermost right postion; in which case, preferably only that portion of the font 2 designated lower case letters (eight selected columns 6 of indicia) can be positioned in the position'of the vertical column 6'. Specifically, upon rotation of the shaft 102, the shaft 28 is rotated via gear 33, gear 36 and housing 35.

In order to shift the mechanism, the solenoid 7 is energized and translates the shaft 28 to the left in a,direction parallel to its longitudinal axis. Longitudinal movement of the shaft 28 to the left produces longitudinal movement of the housing 35 and thus helical gear 36. The gear 33 position is completely established by means of the digital positioner as illustrated in FIGURE 1 of the aforesaid patent. Thus, the gear 33 cannot rotate except under control of the shaft 102 and the engagement with the external helical gear 33. The pitch of the teeth of the gears 33 and 36 is such relative to the stroke of the solenoid 7 that the shaft 28 is rotated through a predesigned are thereby rotating the font 2 through an increment adequate to provide one additional binary digit of positioning. An entire new set of faces of the font 2 is now under control of the shaft 102 so that, upon rotation of that shaft, any one of the eight vertical columns 6 of the latter or shift group may now be placed in the position of the column 6'. Thus, by the addition of a single solenoid 7 and the minor amount of additional mechanism represented by the housing 35 and the gears 33 and 36, the range of the apparatus may be extended two-fold.

Two examples of font and shift arrangements which may be employed are as follows: all eight of the columns which may be printed without shift may be arranged side by side. The digital positioner then will rotate the font 22 /2 for each position for a total rotation of The shift mechanism rotates the font 180 under these circumstances. Alternatively, the shift and non-shift columns may be arranged side-by-side. The digital positioncr now rotates the font 45 for each position and the shift mechanism rotates the font only 22.5". Various other arrangements may be employed without departing from the spirit of the invention.

It should be noted that rotation of the shaft 102 must not produce translation of the shaft 28 since this would result in an indeterminate rotation of the shaft 28 as a result of the action of the gears 33 and 36. The desired result is obtained by the use of a heavy duty spring 37 of sutficient strength to prevent this action when the solenoid 7 is not energized and by employing a high holding force solenoid.

Proceeding now to a description of the apparatusfor selecting the particular horizontal row 4 for purposes of printing, reference is made to FIGURES 1, 4 and 6. The mechanism for efiecting selection of a row 4 comprises a splined shaft 38, a sleeve 39, a pair of gears 41 and 42 and rack gear teeth 43 and 44 formed on the back vertical surface of the type font frame 9. The sleeve 39 is hollow and internally splined so as to mate with splines formed on the shaft 38. The sleeve 39 is secured within the carriage 1 by the same means as the sleeve 24. Secured to the sleeve 39 are the gears 41 and 42 which engage the gears 43 and 44, formed respectively on the rear surfaces, as illustrated in FIGURE 1, of the two sidewalls 13 and 14 of the member 9. Thus, upon rotation of the shaft 38, the gears 41 and 42 rotate and, due to their engagement with their rack gears 43 and 44, produce vertical translation of the frame 9 and therefore of the type font 2.

The shaft 38 is positioned by a digital positioner which is identical with that partially illustrated in FIGURE 9 except perhaps for the fact that the shaft of the digital positioner, such as the shaft 102 of FIGURE 9, is directly connected to the shaft 38 or the shaft 38 is an elongation of the shaft 102. However, this does not mean that an equivalent shift apparatus to the helical gears 33-35 could not be inserted between the digital positioner and shaft 38 if so desired.

Since the type font 2 and, therefore, the frame 9 are supported by the shaft 8 and are freely rotatable about the axis of the stub shafts 17 and 18, a mechanism must be provided for maintaining the rack gears 43 and 44 formed on the surface of the frame 9 in contact with the gears 41 and 42 during the interval of positioning of a row 4 of the font 2 by the apparatus. This function is performed by the same apparatus which performs the printing function in accordance with the present invention. Specifically, and reference is made to FIGURES 5-8 and miscellaneous showings in others of the figures, the printing mechanism comprises a pair of arms 46 and 47 secured together by means of a block 48 arranged behind the carriage 1 as illustrated in FIGURE 1. The arms 46 and 47 have inward projections 49 and 51 extending into vertically arranged grooves 52 and 53 formed in the sides of the sidewalls 13 and 14 of the frame 9. When the arms 46 and 47 are retracted; that is, are positioned in the nonprint position, the projections 49 and 51 engage rear surfaces of the grooves 52 and 53 pulling the frame 9 back against the gears 41 and 42. Thus, positive engagement between the teeth of gears 41 and 43, and 42 and 44, respectively, is insured during the positioning interval.

When it is desired to perform a printing operation, the arms 46 and 47 are moved forward and engage front surfaces 54 and 56, respectively, of the slots 52 and 53. The arms push against these surfaces and produce rotation of the frame 9 and therefore the font 2, about the axis of the stub shafts 17 and 18. The movement thus induced is sufiicient to produce engagement between the font 2 and the platen 5 illustrated in FIGURE 2. It should be noted that upon rotation of the apparatus about the axis of the shafts 17 and 18, the gear 22 becomes partially disengaged from the gear 23 and the gears 43 and 44 become partially disengaged from the gears 41 and 42, respectively. Thus, detenting may be employed to insure the proper positioning of the font 2 both relative to rotation about its longitudinal axis and translation along said axis.

Detenting relative to rotation is provided by a pin 57 adapted to engage a toothed wheel 58 carried on the upper end of the shaft 8. The pin extends downwardly from a horizontal member 59 supported by a vertical member 61 formed as an upward extension of the carriage 1. The pin 57 is positioned relative to the wheel 58 such that, when the mechanisms, the frame 9 and font 2, are in the non-print or retracted position, the pin lies outside of the outer periphery of the teeth formed on the wheel 8. However, the spacing is quite close, and when a printing operation occurs and mechanisms 2 and 9 are moved forward, the pin 57 enters the space between teeth formed in the wheel 58 providing precise positioning of a vertical column relative to the platen 5.

In order to provide detenting in the vertical position, the inward projections 49 and 51 of the arms 46 and 47, respectively, are provided with teeth designated by the reference numeral 62 as viewed in FIG. 8. Horizontally extending pins 63 are provided in the slots 52 and 53 in contact with the surfaces 54 and 56.

When the arms 46 and 47 are moved forward to effect a printing operation, the teeth 62 on projections 49 and 51 engage the pins 63 and correct vertical misalignment of the member 9 and therefore of the font 2. The detenting arrangement provided herein is quite important to the overall operation of the device. Specifically, the apparatus employs a large number of gears in the digital positioner and the interconnecting gear trains and relatively elongated shafts. Normally, backlash in such devices is a severe problem. However, in the apparatus of the present invention, the final and precise positioning of the font 2 is effected by the detenting devices associated with the carriage and material backlash in the system is permissible without sacrificing registration while materially reducing manufacturing costs. Long life is assured since the detenting occurs after the digital positioning devices have become decoupled from the type font.

It will be noted that, during movement of the arms 46 and 47 from their retracted to their print position, the extensions 49 and 51 are out of contact with front and rear surfaces defining the slots 52 and 53. In order to prevent movement of the member 9 and therefore the font 2 during this interval, a compression spring 64 is provided which extends between the bottom of the yoke member 16 and a rear wall of the carriage 1. Thus, as viewed in FIGURE 6, the yoke is biased in a counterclockwise direction so that during a printing operation the rack gears 43 and 44 are maintained in contact with the gears 41 and 42 until the teeth 62 on the inward projections 49 and 51 contact the indexing pins 63 of front surfaces 54 and 56 of the slots 52 and 53.

The mechanism for producing movement of the arms 46 and 47 from their retracted to their print position and back to their retracted position comprises a torque quill arrangement generally designated by the reference numeral 66, a cam 67, a cam follower 68 and a solenoid 69 for controlling a latch 71. More particularly, a hollow shaft 72 has extending therethrough a torque quill 73 which is anchored to a frame member wall 74 as indicated generally at the reference numeral 76. The quill 73 is secured to the hollow shaft 72 at the left end thereof by means of set screws or other similar means (not illustrated). The shaft 72 carries the cam follower 68 suitably secured by arms 77 to the shaft 72 and adapted to ride on cam 67. The quill 73 is initially rotated before being secured to the frame so that the shaft 72 is biased to maintain the cam follower 68 in contact with the cam 67 during all rotational positions of the cam. The cam 67 is secured to a constantly rotating shaft 3. The shaft 3 may be the shaft 3 of FIGURE 1 of the aforesaid patent or may be geared in a one-to-one or other suitable ratio to said shaft as desired.

The shaft 72 also carries an upwardly extending stub shaft 78 notched in its upper surface to receive a latch plate 79 in the notch. The latch plate 79 is maintained in a downward position seated in the notch in the member 78 by means of a compression spring 81. The latch plate carries armature 82 of the electromagnet or solenoid 69 so that, upon energization of the solenoid 69, the latch plate 79 is lifted. When the solenoid 69 is not energized and the latch plate 79 is in the downward position, the cam follower 68 cannot follow the cam 67 and the shaft 72 is not rotated. However, when the solenoid 69 is energized and the latch plate 79 is lifted, the shaft 72 is released and the cam follower 68, under the torque provided by the torque quill 73 remains in engagement with the cam follower 67, following its contours.

During a printing operation, the cam follower 68 and thus shaft 72 rotate clockwise as viewed in FIGURES l and 2, and move the arms 46 and 47 forward or from left to right as viewed in FIGURE 2. Specifically, the shaft 72 has secured thereto an elongated upstanding member 84 coextensive with the travel of the carriage 1. The member 84 is adapted to fit into a groove 86 extending through the arms 46, 47 and the plate 48. When the shaft 72 is permitted to rotate clockwise, the upstanding member 84 also rotates clockwise and translates the arms 46, 47 and plate 48 forward or to the right as viewed in FIGURE 2. If the solenoid 69 has not been energized, the shaft 72 cannot rotate and the arms 46 and 47 are held in their retracted or non-print position.

It should be noted that the arms 46 and 47 are channel members and receive therein guide members 87 and 88 secured to inner surfaces of the carriage 1 in the generally horizontal plane.

The carriage is supported on two rail members 89 and 91 which extend between frame members 29 and 31 and are supported therein. The carriage carries suitable rollers 92 for engagement with the angle member 89 and rollers 93, which engage angle member 91. The rollers 92 and 93 engage four surfaces of the members 89 and 91 and prevent movement of the apparatus in all four directions;

7 namely, up'and down and back and forth as illustrated in FIGURE 1 or up and down and left to right as illustrated in FIGURE 2, permitting free movement only along a direction parallel to the axes of the shafts 28 and 38.

Movement of the carriage is effected by a tape 94, preferably of steel. The tape 94 is driven through a suitable wheel by means of a conventional reversible step motor. In one specific case, the motor is stepped during printing at sixty increments per second and a carriage return is stepped at one hundred twenty intervals per second. Since the entire carriage assembly weighs only approximately 100 grams including the traveling portion of the print actuating mechanism, the type font, etc., no difiiculty is encountered in achieving these speeds.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

I claim:

1. A printing mechanism comprising a carriage, means for mounting said carriage for translatory movement along a predetermined path, a yoke pivotally mounted in said carriage for oscillation about an axis parallel to said predetermined path, a first splined shaft secured to-said yoke and having an axis extending perpendicular to the oscillatory axis of said yoke, a type font slidable along said first splined shaft and having internal splines mating with the splines of said first splined shaft, 21 second splined shaft extending parallel to said predetermined path and passing through said carriage, an internally splined shaft disposed about said second splined shaft and positioned within said housing, means constraining said internally splined shaft to translate with said carriage, the splines of said second and internally splined shafts constraining said internally splined shaft to rotate with said second splined shaft, a first gear secured to said internally splined shaft, a second gear mating with said first gear and secured to said first splined shaft whereby rotation of said second splined shaft produces rotation of said first splined shaft, selection means for rotating said second shaft through a prescribed arc and multiples thereof, said gears being located on one side of the axis of rotation of said yoke, means for rotating said yoke in a direction so as to partially disengage said gears and means for detenting said first splined shaft upon rotation of said yoke.

2. The combination according to claim 1 further comprising a shift mechanism including means for adding a predetermined rotation to said shaft in addition to the rotation produced by said selection means.

3. The combination according to claim 2 wherein said means for adding comprises means for translating said second shaft and means for converting translation of said second shaft to a prescribed rotation thereof.

4. A printing mechanism including a carriage, means for mounting said carriage for translatory movement along a predetermined path, a generally cylindrical type font having indicia arranged in rows and columns about the circumference thereof, means for mounting said type font on said carriage for rotation about and translation along the axis of said cylindrical font, a platen, said means for mounting including means permitting rotation of said font about a second axis remote from the axis of said font so as to present at least one of said indicia to said platen to effect a printing operation, means for inducing rotation of said font about said second axis, said means for inducing rotation including means for detenting said font to prevent translatory movement thereof along its axis.

5. The combination according to claim 4 wherein said means for detenting is transported by said carriage.

6. The combination according to claim 5 wherein said means for detenting includes a member for translating said type font along its axis, said member having indentations formed in a surface thereof, said means for inducing rotation contacting said surface of said member and engaging said indentations to detent said font.

7. A printing mechanism including a carriage, means for mounting said carriage for translatory movement along a predetermined path, a hollow frame having two opposed end means and two opposed side members, means mounting said frame on said carriage for sliding movement along a path parallel to said side members, a generally cylindrical type font having indicia arranged in rows and columns on the circumference thereof, said type font being located in said frame for sliding movement with said frame and rotation relative there-to about the longitudinal axis of said cylindrical type font, and print means for rotating said frame and type font about a further axis perpendicular to the axis of said font and parallel to said predetermined path, said print means comprising a pair of translatable arms, said arms including means for detenting said font relative to said path parallel to said side members upon rotation of said frame and said font about said further axis. v

8. The combination according to claim 7 wherein said means for detenting comprises a slot formed in each of said side members parallel to the axis of said cylindrical type font, said arms including members extending into said slots, said print means moving said arms so as to produce engagement between a surface of each of said members and a surface of its associated slot during a print operation, said surfaces including mating projections to prevent movement of said font.

9. A printing mechanism including a carriage, means for mounting said carriage for translatory movement along a predetermined path, a yoke mounted in said carriage for rotation about an axis parallel to said predetermined path, a firs-t shaft secured to said yoke and extending generally perpendicular to the axis of rotation of said yoke, a hollow generally rectangular frame having opposed end walls and opposed side walls, a cylindrical type font having indicia arranged in rows and columns about the circumference thereof, said type font being positioned in said frame with its longitudinal axis parallel to said sidewalls of said frame, said frame and said type font being positioned on said first shaft with said type font coaxial with said first shaft, said frame and said font being constrained to translate along the axis of said first shaft as a unit, means constraining said type font to rotate with said first shaft, a second shaft, means for incrementally rotating said second shaft as a function of a column of indicia to be selected, means for translating said frame as a function of rotation of said second shaft, a pair of parallel arms engaging opposite ones of said sidewalls of said frame, means for constraining said arms to translate with said carriage and means for concurrently moving both said arms in a direction to rotate said frame about the axis of said yoke and means mounted on said arms to detent said frame.

10. The combination according to claim 9 wherein said means for moving said arms comprises an elongated member extending parallel to said predetermined path, said member having an elongated axially extending shoulder, a recess formed in said arms and fitting over said shoulder, and means for selectively oscillating said member about its elongated axis.

11. A printing mechanism comprising a carriage, means for mounting said carriage for translatory movement along a predetermined path, a yoke pivotally mounted in said carriage for oscillation about an axis parallel to said predetermined path, a first shaft secured to said yoke and having an axis extending perpendicular to the oscillatory axis of said yoke, a type font slidable along and constrained to rotate with said first shaft, a second shaft extending parallel to said predetermined path and passing through said carriage, a hollow shaft disposed about said second shaft and positioned within said housing, means constraining said hollow shaft to translate with said carriage and rotate with said second shaft, a first gear secured to said hollow shaft, a second gear mating with said first gear and secured to said first shaft whereby rotation of said second shaft produces rotation of said first shaft, selection means for rotating said second shaft through a prescribed arc and multiples thereof, said gears being located on one side of the axis of rotation of said yoke, means for rotating said yoke in a direction so as to partially disengage said gears and means for detenting said first shaft upon rotation of said yoke.

12. The combination according to claim 11 wherein said means for detenting comprises a toothed wheel secured to said first shaft and rotatable therewith and means secured to said carriage for engaging said toothed wheel only upon rotation of said yoke about its axis.

13. A printing mechanism comprising a carriage, means for mounting said carriage for translatory movement along a predetermined path, a yoke pivotally mounted in said carriage for oscillation about an axis parallel to said predetermined path, a first shaft secured to said yoke and having an axis extending perpendicular to the oscillatory axis of said yoke, a type font slidable along and constrained to rotate with said first shaft, a second shaft extending parallel to said predetermined path and passing through said carriage, a hollow shaft disposed about said second shaft and positioned within said housing, means constraining said hollow shaft to translate with said carriage and rotate with said second shaft, a first gear secured to said hollow shaft, a second gear mating with said first gear and secured to said first shaft whereby rotation of said second shaft produces rotation of said first shaft, and selection means for rotating said second shaft through a prescribed arc and multiples thereof.

14. The combination according to claim 13 further comprising a shift mechanism including means for adding a predetermined rotation to said shaft in addition to the rotation produced by said selection means.

15. The combination according to claim 14 wherein said means for adding comprising means for translating said second shaft and means for converting translation of said second shaft to a prescribed rotation thereof.

16. A printing mechanism including a carriage, means for mounting said carriage for translatory movement along a predetermined path, a generally cylindrical type font having indicia arranged in rows and columns about the circumference thereof, means for mounting said type font on said carriage for rotation about and translation along the axis of said cylindrical font, a platen, said means for mounting including means permitting rotation of said font about a second axis remote from the axis of said font so as to present at least one of said indicia to said platen to effect a printing operation, means for inducing rotation of said font about said second axis, said means for inducing rotation including a member and an element both mounted on said carriage, said member engaging said type font to produce rotation of said type font about said second axis, upon rotation of said member about said second axis, said element engaging said member to produce rotation of said member about said second axis upon translation of said element, and means for at will translating said element.

17. The combination according to claim 16, wherein said means for at will translating said element, comprises a shaft, means for at will rotating said shaft and means for translating rotation of said shaft into translation of said element.

18. The combination according to claim 17 wherein said means for rotating said shaft comprises resilient means for biasing said shaft toward a first angular position, means for rotating said shaft against the bias of said means for biasing toward a second position and subsequently permitting return to said first position, and means for selectively retaining said shaft in said second position.

19. The combination according to claim 18 wherein said shaft is hollow and said resilient means is a torque quill located interiorly of said hollow shaft.

20. A printing mechanism including a carriage, means for mounting said carriage for translatory movement along a predetermined path, a generally cylindrical type font having indicia arranged in rows and columns about the circumference thereof, means for mounting said type font on said carriage for rotation about and translation along the axis of said cylindrical font, a platen, said means for mounting including means permitting rotation of said font about a second axis remote from the axis of said font so as to present at least one of said indicia to said platen to effect a printing operation, means for inducing rotation of said font about said second axis, said means for mounting comprising a yoke having a pair of arms and pivoted in said carriage at the ends of said arms, a shaft mounted in the base of said yoke for rotation about the axis of said shaft, said type font being mounted on said shaft for rotation therewith, and resilient means for biasing said yoke to maintain said type font out of contact with said platen.

21. The combination according to claim 20 further comprising a frame having two opposed side members, means mounting said frame on said shaft for sliding movement along a path parallel to said side members, said type font being located in said frame for sliding movement with said frame and rotation relative thereto, and print means for rotating said frame and type font about said second axis, said print means comprising a pair of translatable arms, said arms including means for detenting said font upon rotation of said frame and said font about said further axis.

22. The combination according to claim 21 wherein said means for detenting comprises a slot formed in each of said side members parallel to the axis of said cylindrical type font, said arms including members extending into said slots, said print means moving said arms so as to produce engagement between a surface of each of said members and a surface of its associated slot during a print operation, said surfaces including mating projections to prevent movement of said font.

References Cited UNITED STATES PATENTS 446,394 2/1891 Seifried 197-49 1,983,099 12/1934 Sampson 197-49 2,870,897 1/1959 Hubl 197-18 2,951,439 9/1960 Stutz et al. 101-93 3,085,670 4/1963 Paige 197-50 3,089,413 5/1963 MacNeill et al 101-93 3,168,182 2/1965 Bernard et al. 197-18 3,291,041 12/ 1966 Burchfield et al 101-93 FOREIGN PATENTS 577,859 6/1933 Germany.

ROBERT E. PULFREY, Primary Examiner.

E. S. BURR, Assistant Examiner. 

1. A PRINTING MECHANISM COMPRISING A CARRIAGE, MEANS FOR MOUNTING SAID CARRIAGE FOR TRANSLATORY MOVEMENT ALONG A PREDETERMINED PATH, A YOKE PIVOTALLY MOUNTED IN SAID CARRIAGE FOR OSCILLATION ABOUT AN AXIS PARALLEL TO SAID PREDETERMIONED PATH, A FIRST SPLINED SHAFT SECURED TO SAID YOKE AND HAVING AN AXIS EXTENDING PERPENDICULAR TO THE OSCILLATORY AXIS OF SAID YOKE, A TYPE FRONT SLIDABLE ALONG SAID FIRST SPLINED SHAFT AND HAVING INTERNAL SPLINES MATING WITH THE SPLINES OF SAID FIRST SPLINED SHAFT, A SECOND SPLINED SHAFT EXTENDING PARALLEL TO SAID PREDETERMINED PATH AND PASSING THROUGH SAID CARRIAGE, AN INTERNALLY SPLINED SHAFT DISPOSED ABOUT SAID SECOND SPLINED SHAFT AND POSITIONED WITHIN SAID HOUSING, MEANS CONSTRAINING SAID INTERNALLY SPLINED SHAFT TO TRANSLATE WITH SAID CARRIAGE, THE SPLINES OF SAID SECOND AND INTERNALLY SPLINED SHAFTS CONSTRAINING SAID INTERNALLY SPLINED SHAFT TO ROTATE WITH SAID SECOND SPLINED SHAFT, A FIRST GEAR SECURED TO SAID INTERNALLY SPLINED SHAFT, A SECOND GEAR MATING WITH SAID FIRST GEAR AND SECURED TO SAID FIRST SPLINED SHAFT WHEREBY ROTATION OF SAID SECOND SPLINED SHAFT PRODUCES ROTATION OF SAID FIRST SPLINED SHAFT, SELECTION MEANS FOR ROTATING SAID SECOND SHAFT THROUGH A PRESCRIBED ARC AND MULTIPLES THEREOF, SAID GEARS BEING LOCATED ON ONE SIDE OF THE AXIS OF ROTATION OF SAID YOKE, LOCATED ON ONE SAID YOKE IN A DIRECTION SO AS TO PARTIALLY DISENGAGE SAID GEARS AND MEANS FOR DETENTING SAID FIRST SPLINED SHAFT UPON ROTATION OF SAID YOKE. 